Naturally occurring vapor-liquid-solid (VLS) Whisker growth of germanium sulfide

Mineralogy of Burning-Coal Waste Piles in Collieries of the Czech Republic

“…The same compound is reported from burning-waste piles of some Pennsylvanian collieries Finkelman et al, 1974). The phase is associated with GeSnS 3 and greenockite.…”

Scanning electron microscope observations of sublimates from Merapi Valcano, Indnesia.

“…The growing edge of the crystal is in contact with the liquid, and sometimes quenched droplets of liq uid are preserved on the crystals (Givargizov, 1987). Such droplets occur on the tips of GeS2 whiskers collected from burning anthracite deposits, evidence that the VLS mechanism also occurs in nature (Finkelman et al, 1974). However, the absence of quenched droplets on any of the Merapi sublimates suggests that these crystals precipitate directly from the gas and not from the VLS process.…”

Mineralogy of the Burning Anna I Coal Mine Dump, Alsdorf, Germany

“…VLS crystallization was observed for germanium sulfide, GeS 2 , from a burning coal seam at Forestville, Pennsylvania, USA (Finkelman et al, 1974). First, a drop of melt is formed from the gas phase.…”